Syndiotactic polystyrene is a highly crystalline thermoplastic resin with a high melting point (in the 260.degree.-285.degree. C. range), a high crystallization rate, high chemical resistance and excellent mechanical properties which qualify it as thermoplastic engineering resin.
N. Ishihara et al, in a series of patents (Eur. Pat. Appl. EP 210,615, EP 275,943, Jpn. Kokai Tokkyo Koho JP 03 59,010) proposed a number of catalysts which can be employed for syndiospecific polymerization of styrene and its ring-substituted derivatives. All these catalysts include two components. The first component is a titanium compound, such as titanium tetraethoxide, cyclopentadienyltitanium trichloride, solid titanium-containing compounds derived from titanium tetrachloride, and tetrabenzyltitanium. The second component of their catalyst systems is methylaluminoxide which is produced by reacting trimethylaluminum (TMA) either with free water or with hydrates of inorganic salts, such as CuSO.sub.4.5H.sub.2 O. The said titanium compounds are inactive for styrene polymerization if, instead of methylaluminoxane, they are combined solely with trialkylaluminum compounds, such as TMA.